Improvement of continuous arteriovenous hemofiltration (CAVH) and hemofiltration (HF) efficiency by adding hemoperfusion (HP).

Aiming to improve the efficiency of the blood purification convective methods either with spontaneous (CAVH) or with pump-assisted (HF) extracorporeal circulation we inserted after the hemofilter a cartridge containing 70 g of collodion-coated activated charcoal (CAC) microencapsulated, obtaining so hemofiltration and hemoperfusion in series (HF+HP). The obtained results show that in both methods HP addition gives a negligible increase of urea clearance and a practically null increase of phosphate clearance, whereas creatinine and uric acid clearances increase is remarkable especially, in percentage, with low blood flows (CAVH). In the HF+HP system we have also been studying B2-microglobulin (B2-M) clearance aiming at examining the possibility of increasing the removal of substances with higher molecular weight. We have been finding HP addition increases further on B2-M clearance already high in HF. Therefore we think HP addition to convective methods is an interesting step in the attempt to carry out highly efficient blood purification methods.